What is a servo press?

A servo press uses servo motors for precise force and position control during forming operations.

How do I calculate servo press tonnage?

Use our free tonnage calculator at servopress.club/tonnage-calculator.html

Q: Servo press vs. hydraulic press for deep drawing - which is better and why?

admin

**Question from a forum member:**
We are evaluating equipment for a new deep drawing line for stainless steel kitchen sinks (draw depth 120mm, material 0.8mm 304 SS). Currently using hydraulic presses. Our sales rep is pushing servo presses hard. What are the real differences for deep drawing specifically?

---

**Answer:**

For deep drawing of stainless steel at 120mm depth, servo presses have genuine advantages over hydraulic - but the decision depends on your volume and budget.

## Speed: Servo Wins Significantly

Hydraulic press for 120mm deep draw: typically 8-15 SPM (limited by hydraulic cylinder speed and return time).

Servo press for same application: 20-35 SPM is achievable with optimized motion profile.

At 25 SPM vs. 12 SPM, a servo press produces twice the parts per shift. For a high-volume sink line, this difference pays for the price premium in 2-4 years.

## Motion Control: Servo Wins

This is the biggest technical advantage for deep drawing.

Hydraulic presses have limited motion control - you can adjust speed and pressure, but the motion profile is relatively fixed.

Servo presses can program the exact velocity at every point in the stroke:
- Slow approach to material (reduces impact marking on stainless)
- Controlled drawing speed (critical for stainless - too fast causes tearing)
- Dwell at BDC (reduces springback)
- Fast return (maximizes SPM)

For 304 stainless at 0.8mm, the optimal drawing speed is 50-80mm/s. A servo press can hold this precisely throughout the draw. A hydraulic press speed varies with load.

## Force Consistency: Hydraulic Wins (Slightly)

Hydraulic presses maintain constant force throughout the stroke - the pressure is set and the cylinder delivers that force regardless of position.

Servo presses deliver force based on motor torque, which varies with speed. At very low speeds (end of draw), servo presses can deliver high torque, but the force curve is different from hydraulic.

For most deep drawing applications this does not matter. For very deep draws (draw ratio above 2.5) or difficult materials, hydraulic force consistency can be an advantage.

## Blank Holder Force: Depends on Configuration

For deep drawing, blank holder force control is critical. Both press types can be configured with:
- Fixed blank holder (simple, less control)
- Hydraulic cushion (good force control, works with both press types)
- Servo cushion (best control, typically paired with servo press)

A servo press with servo cushion gives you independent control of punch speed and blank holder force throughout the draw - the best possible setup for difficult materials.

## Cost Comparison

- Hydraulic press 200-ton: $150,000-$250,000
- Servo press 200-ton: $300,000-$500,000

The servo press costs 2x more upfront. At 2x the production rate, the economics favor servo for volumes above ~500,000 parts/year.

## Recommendation for Your Application

For 304 SS kitchen sinks at production volume: servo press with hydraulic cushion. The motion control advantage for stainless is significant, and the speed advantage justifies the cost at production volumes.

If you are doing prototype or low-volume work (under 100,000 parts/year), keep the hydraulic press.

mike_chen_eng

We had the exact same F30015 issue on a 160T Aida last year. Root cause: encoder cable running too close to servo motor power cable — induced noise caused position feedback errors. Rerouted with 30cm separation and added ferrite cores. Zero F30015 alarms in 8 months since.

dave_toolmaker

For stainless steel kitchen sinks specifically, I'd go servo. I've built dies for both press types for this exact application. The servo's controlled approach speed eliminates the surface scratching you get with hydraulic presses when the punch first contacts the blank. For a consumer product where surface finish matters, that's a big deal.